I took the Airport city line to Phaya Thai and walked 5mins from the station to the hotel, it is really easy to find if you search 'True Siam Hotel' from Gxxgle map, however if you book it from Airbnb, the map on Airbnb would guide you to BTS Sanam Pao somehow and this is wrong... Don't follow Airbnb map!!!
The Staffs are so kind!! they apologized to me a lot for not having a queen size bed room but a room with 2 single beds instead, which is totally okay, it is not a problem at all!! Thay are too kind to say sorry for that.
And they kept my luggage after I checked out because my flight is at mignight, so that I can spent my last day in Bangkok without carrying a big suitcase, they are really nice persons!
The room is so big and clean!! You have everything you need!! I didn't eat there, but I had a look on the room service menu, the menu and price are pretty reasonable, I would live there again for sure next time I go to Bangkok.